An old windows 10 laptop with ISTA+ installed. This gets you a shop manual, code scanning, adaptions reset, diagnostics and testing of components and so on.

Cable here:
https://www.bimmergeeks.net/product-...eeks-pro-cable

Software here:
https://www.bimmerfest.com/forums/sh....php?t=1023698

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2009 35d, 2006 325i & 330i